气相色谱法测定多溴联苯的蒸气压

采用气相色谱法,以二氯二苯三氯乙烷(DDT)为参考化合物,测定了6个多溴联苯(PBBs)在不同温度条件下的蒸气压, 然后使用Slide数理统计软件、以最小二乘法回归计算出Antoine方程的A,B,C参数,从而建立了6个PBBs的蒸气压与温度 的关联式。初步探讨了分子连接性指数与蒸气压的相关性,结果发现一阶拓扑指数与蒸气压表现出很好的线性关系,两者 的相关系数的平方大于0.99,标准偏差小于0.08。     

Characteristics of selective oxidation during the fabrication of vertical cavity surface emitting laser

Taking into account oxidation temperature, N₂ carrier gas flow, and the geometry of the mesa structures this paper investigates the characteristics of selective oxidation during the fabrication of the vertical cavity surface emitting laser (VCSEL) in detail. Results show that the selective oxidation follows a law which differs from any reported in the literature. Below 435℃ selective oxidation of Al_0.98Ga_0.02As follows a linear growth law for the two mesa structures employed in VCSEL. Above 435℃ approximately increasing parabolic growth is found, which is influenced by the geometry of the mesa structures. Theoretical analysis on the difference between the two structures for the initial oxidation has been performed, which demonstrates that the geometry of the mesa structures does influence on the growth rate of oxide at higher temperatures.     

直接鉴别超重元素Z和A的一种新的可能方法

随着合成的超重元素向超重岛逼近,合成截面越来越小,同时,合成的超重元素的寿命可能相对增长, 这对利用α衰变链的传统方法鉴别超重元素是非常不利的。 讨论了可能突破这个瓶颈的一种可以直接鉴别超重元素原子序数Z和质量A的新方法, 即与RFQ离子阱技术相结合的激光多步共振电离方法, 对实现这种方法的途径、 该方法所面临的困难和挑战、需要进行的前期研究工作以及该方法的可能性和可行性进行了较详细的讨论。 With the synthesis of heavy elements approaching the super heavy island, the production cross section becomes smaller and the lifetime of the super heavy element becomes longer, which results in the difficulties for identification of theelements by using conventional alpha decay chain technique. In order to overcome the difficulties, a novel approach to direct identification of atomic number Z and nuclear mass A for super heavy elements is proposed, namely, the multi step resonant laser ionization of singly charged ions in combination with RFQ trap. The routine for the experiment is presented, and the possibilities, feasibilities, as well as the problems to be faced, are discussed in detail.     

基于SPSS的教职工健康体检数据分析研究——以宁波大学为例

为尽早预防疾病, 开展健康管理, 改善教职工的健康现状, 对2018—2021年期间宁波大学教职工的健康体检资料采用SPSS 23.0软件进行统计分析. 结果表明 2018—2021年检出前10种疾病略有不同, 4年间检出率均位于前10位的疾病有甲状腺结节、肺结节、血脂异常、高尿酸血症、心电图异常、乳腺异常. 其中每年血脂异常、肺结节及高尿酸血症检出率男性高于女性(P< 0.05), 甲状腺结节的检出率则是女性高于男性(P<0.05); 甲状腺结节、肺结节和高尿酸血症的检出率呈现逐年升高趋势(P<0.05); 每年检出的疾病随年龄变化的态势各不相同, 其中血脂异常、甲状腺结节、肺结节、心电图异常、前列腺异常的检出率随着年龄的增长而增加(P<0.05). 表明慢性非传染性疾病已成为影响教职工健康的首要危险因素. 因此, 应倡导科学的生活方式, 积极进行健康体检, 建立健康管理档案, 并进一步强化健康管理理念和教职工的健康意识, 尽可能改善教职工的健康状况.     

Improving nucleation in the fabrication of high-quality 3D macro-porous copper film through the surface-modification of a polystyrene colloid-assembled template

A new approach is developed to the fabrication of high-quality three-dimensional macro-porous copper films. A highly-ordered macroporous copper film is successfully produced on a polystyrene sphere (PS) template that has been modified by sodium dodecyl sulfate (SDS). It is shown that this procedure can change a hydrophobic surface of PS template into a hydrophilic surface. The present study is devoted to the influence of the electrolyte solution transport on the nucleation process. It is demonstrated that the permeability of the electrolyte solution in the nanochannels of the PS template plays an important role in the chemical electrodeposition of high-quality macroporous copper film. The permeability is drastically enhanced in our experiment through the surface modification of the PS templates. The method could be used to homogeneously produce a large number of nucleations on a substrate, which is a key factor for the fabrication of the high-quality macroporous copper film.     

Dopant diffusion and surface morphology of vanadium implanted 4H-silicon carbide

The diffusion behaviours of vanadium implanted p- and n-type 4H-SiC are investigated by using the secondary ion mass spectrometry (SIMS). Significant redistribution, especially out-diffusion of vanadium towards the sample surface is not observed after 1650℃ annealing for both p- and n-type samples. Atomic force microscopy (AFM) is applied to the characterization of surface morphology, indicating the formation of continuous long furrows running in one direction across the wafer surface after 1650℃ annealing. The surface roughness results from the evaporation and re-deposition of Si species on the surface during annealing. The chemical compositions of sample surface are investigated using x-ray photoelectron spectroscopy (XPS). The results of C 1s and Si 2p core-level spectra are presented in detail to demonstrate the evaporation of Si from the wafer and the deposition of SiO₂ on the sample surface during annealing.     

生物催化不对称合成beta-羟基酸衍生物

手性β-羟基酸及其衍生物是应用化工和有机合成的关键中间体, 生物催化的不对称合成方法以其绿色环保, 简洁高效及高立体选择性已然成为一个新兴的研究热点。本文较系统的总结了生物催化的β-羟基酸及其衍生物不对称合成研究工作,重点介绍了脂肪酶,腈代谢酶及还原酶在合成手性β-羟基酸衍生物中的应用。最后,对今后生物催化不对称合成β-羟基酸的发展方向做一展望。     

一步法制备纳米氧化锌的形成机理

以氯化锌和氢氧化钠为原料,采用直接水解一步法制备了针状和球形纳米氧化锌.借助于XRD、TEM等测试手段,对纳米氧化锌粉体的制备条件和其对粒度、形貌的影响进行了分析研究.利用负离子配位多面体生长基元理论模型,解释了直接水解合成氧化锌纳米晶体的形成机理和生长习性.研究结果表明,一步法直接合成纳米氧化锌的结晶过程遵循溶解-结晶-聚集生长机理模型;ZnO为极性晶体,具有极性生长特性,其成核过程包括均相成核和非均相成核.     

片层硅酸盐用于热固性PU/PLS复合可能性探讨

高岭土(Kaolinite)和蒙脱土(Montromollite)等粘土,被广泛用作添加剂来改善聚合物的耐热性能。文章用各种先进技术对高岭土与蒙脱土的形态、组成和结构进行表征比较。电子透射电镜及电子探针(TEM/EDX)结果显示高岭土较蒙脱土有较大的粒径和较小的硅铝比,TEM还显示出这些粘土是由片层粒子堆积而成。热重分析(TGA)的结果表明蒙脱土由于失去吸附水从60 ℃升温至90 ℃失重明显(约7%),而高岭土在此温度下几乎不失水。高岭土脱除结构羟基官能团脱水失重的温度大约在510 ℃,低于蒙脱土的670 ℃。室温下光声傅里叶变换(PAS-FTIR)红外光谱显示蒙脱土在羟基吸收区有较强的吸附水的吸收,1 650 cm-1处孤立的弱吸收谱带可给予左证。变温红外和TGA的结果显示,片层硅酸盐表面的结构羟基从100～500 ℃非常稳定,它可以和异氰酸酯基团(NCO)封端的预聚物反应形成热固性PU/PLS复合聚合物。     

超高效液相色谱-串联质谱法检测蘑菇中6种蘑菇毒素的不确定度评定

以BJS 202008《蘑菇中α-鹅膏毒肽等6种蘑菇毒素的测定》方法为基础,参照JJF 1059.1—2012《测量不确定度评定与表示》和CNAS-GL006《化学分析中的不确定度评估指南》建立相关数学模型,对高效液相色谱-串联质谱法检测蘑菇中6种蘑菇毒素的不确定度来源进行分析与评定,包括样品重复测量、液相色谱-串联质谱仪、标准溶液配制、标准曲线拟合、样品处理。通过计算各个不确定度分量,得到测量结果的合成相对标准不确定度和扩展不确定度。蘑菇中6种蘑菇毒素质量分数测定结果为136.4～141.4μg/kg时,扩展不确定度为3.98～5.74μg/kg(k=2)。测定结果的不确定度主要受样品重复测量和标准溶液配制的不确定度影响。